Fake or Real?

Compression artifactsThe more an image is compressed,
the blockier or grainier it will appear. This blockiness or graininess should
be consistent throughout the image.

ContactWhere two objects in an image meet and their effect on
each other

Drop shadowA shadow offset from an object or person in an image

GranularityRefers to compression artifacts

Hot spotA reflection of a camera flash or other light source,
which creates a bright spot or spots in an image

Noise or specklePixels or specks of an image that are the wrong
color or shade

Red eyeWhere the camera flash causes a person's irises to
be red instead of black

Small white specularityThe white dots seen in
people's eyes, which reflect the lighting in a room or outdoors

Seeing is no longer believing in our modern digital
world. Powerful photo-manipulation software is available to anyone who seeks
it. And according to digital forensics expert Hany Farid, improved forging
technologies make it more important now than ever to look at photographs with a
discerning eye. We asked Farid to scrutinize several photographs of NOVA
scienceNOW host Neil deGrasse Tyson with different celebrities and then
determine which were forgeries that we created.

Below, try your hand at differentiating doctored from untouched photos (acknowledging, of course, that Farid likely had a lot more technology and experience at his disposal than you do). Once you've made up your mind for each image, click on "Fake" or "Real" and then hear what Farid has to say about it. For tips on what to look for when examining photos for authenticity, see the glossary at left.

Hany Farid is the founder of digital forensics, a scientific field designed to determine if digital images, audio, video, and other documents have been manipulated or altered in any way. He runs the Image Science Lab at Dartmouth College.

This feature was produced by Rima Chaddha with audio editing by David Levin.